There already exist various patent documents of the background art, concerning containers for pizzas and generally for warm food.
Cardboard-made containers are widespread but their drawback is that they do not insure a perfect sealing; this drawback is very serious if a warm food (for instance a pizza) comprises liquids that may drip during its transportation from the place where it is sold to that where it is eaten.
Therefore, a great number of pizza sellers prefer—for their clients—to use plastic-made containers that usually include two circular parts, wherein one of them forms the dish (plate) and the other the cover.
The cover and dish are coupled to each other by a joint at their circumference, along the edge of their raised side walls. Provided the packaging is always held in a substantially horizontal position, no leakage of liquids will occur since the plastic-made dish does not present any hole or discontinuity.
Plastic-made containers of the background art have many features which differentiate them from each other, but they also have features in common. Some embodiments exist with a dish or tray made of plastics arranged within a cardboard-made container (see e.g. U.S. Pat. No. 6,601,758).
It has now become usual to provide, on the cover, a plurality of vent holes for the vapour (steam) developed by the warm food, in order to preserve food fragrance. Said vent holes for the vapour (which in this way can escape to the outside) serve to prevent condensate formation inside the plastic packaging and are described—for instance—in the European Patent Application EP 1 112 946 A1.
However, in this latter patent application and in the other documents belonging to the background art, that are known to the inventor of the present patent application, the aforementioned vent holes or apertures are arranged along the outside or peripheral edge (peripheral circumference) of the pizza container or warm food container. Actually, EP 1 112 946 A1 highlights the importance of a solution according to which the plastic-made container has a noticeable thickness of its cover and dish, and a density gradient of the plastic material, thereby insuring a greater resistance to impacts on its external side, and having a foam material inside in order to obtain an improved thermal insulation.
However, since the vent apertures for the vapour (steam) are arranged along the outer edge of the cover, when the pizza is put inside the container these apertures will be located near the crust of the pizza and not near the central part of the pizza where—actually—the most part of the vapour is formed. It follows that the background art does not generally disclose an efficient system to let the vapour (steam) escape to the outside, which system is in fact indispensable to avoid condensate formation inside the plastic-made container and therefore to maintain the fragrance of the pizza up to the moment when it is eaten.
An object of the present invention is to provide a container for a pizza and for other kinds of warm food, which is designed to promote the escape of condensate to the outside of the plastic-made container in a much more efficient manner than traditional containers.
A further object of the present invention is to let the type of food (or the type of pizza) contained inside the packaging be visible (be recognisable) from outside. Still another object of the invention is to provide a product having a convenient cost and allowing a perfect sealing on the dish side (lower part of the packaging), and moreover, which is capable of resisting to heat.
Other specific advantages of the present invention with respect to the background art will be emphasised in the following detailed, non-binding description of a preferred embodiment.